• ‘The Big Bang Theory’ Season 10 episode 1 spoilers, airdate: What happens next revealed plus possible premiere date

‘The Big Bang Theory’ Season 10 episode 1 spoilers, airdate: What happens next revealed plus possible premiere date (Photo : Facebook/The Big Bang Theory/ CBS)

"The Big Bang Theory" Season 9 episode 17 celebrates a milestone in the history of the series. CBS is set to air the 200th episode of its fan-favourite sitcom starring Johnny Galecki (Leonard), Kaley Cuoco (Leonard), Jim Parsons (Sheldon), Kunal Nayyar (Raj), Simon Helberg (Howard) and more. Here are the spoilers for the highly-anticipated segment that will see the return of some old characters for the big celebration. Read on to find out what happens next and where to watch it online via live stream.

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[Spoiler alert! This article contains spoilers for "The Big Bang Theory" Season 9 episode 17. Read on only if you wish to know more about it.]

The 200th episode or as fans call it "BBT200" is titled "The Celebration Experimentation." On this day, Sheldon and his friends will celebrate Sheldon's birthday.

Sheldon is going to receive quite a lot of surprises as the festivities begin. However, everyone is excited by Sheldon himself. According to the Spoiler TV's synopsis for "The Big Bang Theory" Season 9 episode 17, after more than nine years together, the entire gang will come together to celebrate their friend's big day. And it seems they have planned a huge surprise for Sheldon that will leave him amazed. A special guest

More details tease the return of some familiar faces, such as Christine Baranski as Dr. Beverly Hofstadter, John Ross Bowie as Barry Kripke, Sara Gilbert as Leslie Winkle and Will Wheaton as himself. Meanwhile, the special guest is Adam West, who will appear as himself and surprise Sheldon.

West is known for his portrayal of Batman in the 1960s ABC campy series "Batman." It seems like Sheldon is a huge fan of the legendary actor. So his friends arrange to invite the man himself for the big moment.

It is said that the plot of the 200th episode is being kept under the wraps. Meanwhile, a couple of promo videos have been released. The above-mentioned publication has obtained four trailers teasing the events of "The Big Bang Theory" Season 9 episode 17.

The first one shows girls preparing for Sheldon's birthday party as they ask Sheldon questions related to his likings. The second promo video for "The Celebration Experimentation" shows the boys discussing what to gift Sheldon for his birthday. That's when Leonard comes up with the idea of inviting Adam West to the birthday bash.

In sneak peek 3, Amy breaks the news to Sheldon about celebrating his birthday. It seems Sheldon doesn't feel the same about the idea. As for the fourth trailer, it teases the biggest party of the year and Sheldon's reaction when he sees his idol. Click here to watch the promo videos.

"The Big Bang Theory" Season 9 episode 17 "The Celebration Experimentation" airs Thursday at 8:00 pm on CBS. Fans can also watch the 200th episode online via live stream on cbs.com after the segment goes live. Meanwhile, spoilers for episode 18 are expected soon.